Chung stuns Novak

Federer in last 8; Sandgren overcomes Thiem

Serbia's Novak Djokovic (R) congratulates South Korea's Chung Hyeon after losing the men's singles fourth round match of the Australian Open in Melbourne yesterday. Photo: AFP

Afp, Melbourne

Wounded 12-time Grand Slam winner Novak Djokovic was sent tumbling out of the Australian Open by Korean giant-killer Chung Hyeon Monday, but ice-cool Roger Federer roared into the quarterfinals.

The Serb, who was returning from six months out with a right elbow injury, was clearly in pain as his hopes of a seventh Melbourne Park title were extinguished on Rod Laver Arena 7-6 (7/4), 7-5, 7-6 (7/3).

He was keen not to take away from the glasses-wearing Chung's huge achievement after the 21-year-old followed up his win over fourth seed Alexander Zverev in the last round.

"Congratulations. Amazing," said Djokovic, who also had an apparent hip or groin problem, screeching at times when stretching for the ball.

"He was the better player on court today and he deserved to win."

Djokovic said the injuries started troubling him at the end of the first set and a decision on where he goes from here would be made after talking with his medical team.